@article{ValentinoSgambitterraFurgiueleetal., author = {Valentino, Piergiorgio and Sgambitterra, Emanuele and Furgiuele, Franco and Romano, Marco and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Mechanical characterization of basalt woven fabric composites}, series = {Frattura ed Integrit{\`a} Strutturale (Fracture and Structural Integrity)}, volume = {8}, journal = {Frattura ed Integrit{\`a} Strutturale (Fracture and Structural Integrity)}, number = {28}, doi = {10.3221/IGF-ESIS.28.01}, pages = {1 -- 11}, abstract = {Basalt fabric composite, with different twill wave reinforcements, i.e. twill 2/2 and twill 1/3, have been studied in this work by means of experimental tests and numerical finite element (FE) simulations. As fabric reinforcements show repeating undulations of warp and fill yarn, simple mixtures law cannot be applied. As a consequence, the mesoscopic scale, lying between the microscopic and the macroscopic one, has to be taken into account to mechanically characterize a fabric reinforced composite. The aim of this work is to evaluate the stiffness of a fabric reinforced composite in warp and fill direction. In particular a numerical FE model, assuming elliptical sections and sinusoidal shape of the yarns, has been implemented and experimental tests have been carried out in order to validate the proposed model. Finally, the strength and the failure modes le orientation, have been experimentally investigated.}, language = {en} } @inproceedings{SchmidBrulandEhrlichetal., author = {Schmid, Vinzent and Bruland, Matthias and Ehrlich, Ingo and Kastenmeier, Andreas}, title = {Entwicklung und Regelung eines hydraulischen Biegepr{\"u}fstands}, series = {Virtuelle Instrumente in der Praxis 2015 - Begleitband zum 20. VIP-Kongress.}, booktitle = {Virtuelle Instrumente in der Praxis 2015 - Begleitband zum 20. VIP-Kongress.}, editor = {Rahman, Jamal and Heinze, Ronald}, publisher = {VDE-Verlag}, address = {Berlin/Offenbach}, language = {de} } @article{RomanoEisenriedJungbaueretal., author = {Romano, Marco and Eisenried, Michael and Jungbauer, Bastian and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Influence of parameters of the production process on the material quality of unidirectionally reinforced prepregs}, series = {Journal of Achievements in Materials and Manufacturing Engineering (JAMME)}, volume = {68}, journal = {Journal of Achievements in Materials and Manufacturing Engineering (JAMME)}, number = {1}, pages = {32 -- 44}, abstract = {Purpose: A prepreg production device in laboratory scale is used to develop the production process of unidirectionally reinforced prepregs. Design/methodology/approach: The aim of the prepreg production device is to impregnate different types of reinforcement fibers with an arbitrarily selectable thermoset matrix system that completely satisfies the requirements for autoclave processing. As the prepreg production device is designed and built up modularly every module corresponds one step in the process. Findings: To identify the parameters of the production process and investigate its sensitivity on the material quality of both the prepreg as an uncured semi-finished product and the composite as the cured material experimental investigations regarding the resin flow, fiber volume content, mass per unit area and void content are carried out. Overall four material combinations have been investigated, where in each case the selected impregnation temperature and the width of the impregnation gap has been reproducibly varied in selected steps. Research limitations/implications: The experimental characterization of the prepregs and of the composite material is carried out according to German standards.}, language = {en} } @article{RomanoEhrlichGebbeken, author = {Romano, Marco and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites: analytical and numerical investigations}, series = {Frattura ed Integrit{\`a} Strutturale (Fracture and Structural Integrity)}, volume = {11}, journal = {Frattura ed Integrit{\`a} Strutturale (Fracture and Structural Integrity)}, number = {39}, doi = {10.3221/IGF-ESIS.39.22}, pages = {226 -- 247}, abstract = {A parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites is investigated by analytical and numerical investigations. Due to the definition of plain representative sequences of balanced plain-weave fabric reinforced single layers based on sines the variable geometric parameters are the amplitude and the length of the ondulation. The mesomechanic kinematic can be observed in both the analytic model and the FE-analyses. The analytic model yields hyperbolic correlations due to the strongly simplifying presumptions that neglect elasticity. In contrast the FE-analyses yield linear correlations in much smaller amounts due to the consideration of elastic parts, yet distinctly.}, language = {en} } @article{SieglEhrlich, author = {Siegl, Marco and Ehrlich, Ingo}, title = {Transformation of the Mechanical Properties of Fiber-Reinforced Plastic Tubes from the Cartesian Coordinate System into the Cylindrical Coordinate System for the Application of Bending Models}, series = {Athens Journal of Technology \& Engineering}, volume = {4}, journal = {Athens Journal of Technology \& Engineering}, number = {1}, pages = {47 -- 62}, abstract = {Fiber-reinforced plastic (FRP) tubes are used in many different industries, such as electrical engineering and pipeline construction. The tubes are frequently subjected to bending loads, depending on the application. In order that the dimensioning of the tubes can be ensured, analytical bending models are used to calculate the resulting stresses, strains and displacements in the individual layers of the laminate. This enables the making of a statement about the failure of the fiber-reinforced tube by choosing an appropriate failure criterion. For the use of these bending models, it is necessary to understand the respective underlying theory. The theory provides the basis for the mathematical description of the mechanical properties for a single-layered tube and using the relationships between the stresses and strains that occur in the Cylindrical coordinate system for this calculation step. For this reason, a redefinition of the compliance matrix from the transformation about the winding angle to the Cylindrical coordinate system and a modification of the stress and strain vectors is necessary, because the defined Cartesian coordinate system of the model cannot be used for wounded FRP tubes. The transformation causes an exchange of entries in the compliance matrix, which remain in the correct relationship between the particular stress and strains. This step is not specified and may lead to incorrect results due to the incorrect entry of compliances. The present publication refers to sketch on this issue and represent a simplification of the changeover to the level required by the bending models notation of vectors in the form of a permutation. In addition, a new name for the pre-acquisition of the redefined compliances is given to prevent confusion when entering the material law of a bending model. Finally, the permuted and redefined compliances are proved in an example to determine their accuracy.}, language = {en} } @techreport{SieglEhrlichSiegletal., author = {Siegl, Marco and Ehrlich, Ingo and Siegl, Marco and Ehrlich, Ingo}, title = {Einfluss von Prozessparametern auf die Schmelzimpr{\"a}gnierung zur Herstellung von faserverst{\"a}rkten Thermoplasten}, series = {Forschung 2018 / Ostbayerische Technische Hochschule Regensburg}, journal = {Forschung 2018 / Ostbayerische Technische Hochschule Regensburg}, editor = {Baier, Wolfgang}, publisher = {VMK Verlag f{\"u}r Marketing \& Kommunikation GmbH \& Co. KG}, organization = {Ostbayerische Technische Hochschule Regensburg}, pages = {72 -- 73}, abstract = {Die Erforschung von faserverst{\"a}rkten Kunststoffen (FVK) mit thermoplastischer Matrix ist aufgrund der Schweißeignung als Verbindungstechnologie, der thermischen Umformbarkeit, der Recyclebarkeit sowie der verk{\"u}rzten Prozesszeiten im Vergleich zu den vorwiegend eingesetzten faserverst{\"a}rkten Duroplasten erstrebenswert. Die Wechselwirkung zwischen den physikalischen, mechanischen und geometrischen Parametern erh{\"o}ht den Komplexit{\"a}tsgrad des Herstellungsprozesses. Ziel ist daher die Entwicklung einer Impr{\"a}gniertechnik, die eine Fasertr{\"a}nkung mittels eines Thermoplastschmelzbades erm{\"o}glicht.}, language = {de} } @misc{JudenmannPongratzEhrlichetal., author = {Judenmann, Anna and Pongratz, Christian and Ehrlich, Ingo and H{\"o}fer, Philipp and Holtmannsp{\"o}tter, Jens}, title = {Additive Fertigung von endlosfaserverst{\"a}rkten Kunststoffstrukturen}, series = {M{\"u}nchner Leichtbauseminar 2022, 26. October 2022, 16. November 2022, 30 November 2022, Munich/Neubiberg/Garching}, journal = {M{\"u}nchner Leichtbauseminar 2022, 26. October 2022, 16. November 2022, 30 November 2022, Munich/Neubiberg/Garching}, abstract = {Additive Fertigung hat sich in zahlreichen industriellen Anwendungen etabliert und bildet eine wichtige Schl{\"u}sseltechnologie. Im Gegensatz zu metallischen Werkstoffen, haben additiv gefertigte Bauteile aus Kunststoffen geringere Festigkeit und Steifigkeit, sodass sich ihre Verwendung als lasttragende Strukturen schwierig gestaltet. Insbesondere der Einsatz von endlosen Verst{\"a}rkungsfasern kann die mechanischen Eigenschaften additiv gefertigter Strukturen signifikant verbessern und die Fertigung hochbelastbarer Faserverbundstrukturen im 3D-Druckverfahren erm{\"o}glichen. Daher gilt es aktuell notwendige Anlagen und Prozessketten f{\"u}r den Fertigungsprozess aber auch Vorgehensweisen f{\"u}r die belastungsoptimierte Auslegung der Faserverl{\"a}ufe innerhalb des Bauteils zu entwickeln, um so das Themengebiet „Endlosfaserverst{\"a}rkter 3D-Druck" weiter voranzutreiben. F{\"u}r mehr r{\"a}umliche Freiheit bei der Positionierung der Druckbahnen k{\"o}nnen industrieroboterbasierte Systeme eingesetzt werden, um so das Potenzial gerichteter Bauweise von Faserverbundstrukturen auch im additiven Fertigungsprozess vollumf{\"a}nglich aussch{\"o}pfen zu k{\"o}nnen. Dabei erm{\"o}glicht ihr Einsatz auch eine r{\"a}umliche Ablage der Faserverst{\"a}rkung, wobei f{\"u}r die Materialablage ein geeigneter 3D-Druckkopf erforderlich ist. F{\"u}r die Implementierung der Faserverst{\"a}rkung ist zudem eine dem Lastfall entsprechende Auslegung des Bauteils sowie die Ermittlung einer sinnvollen Faserpositionierung innerhalb des Bauteils erforderlich, wobei unterschiedliche Variablen aus den Bereichen Material, Struktur und Fertigungsprozess ber{\"u}cksichtigt werden m{\"u}ssen. Im Rahmen des Vortrages werden die Herausforderungen der Technologieentwicklung des endlosfaserverst{\"a}rkten 3D-Drucks aufgegriffen sowie auf eine belastungsorientierte Faserpositionierung n{\"a}her eingegangen. Aktuelle Erkenntnisse werden diskutiert sowie eine Entwurfsmethodik f{\"u}r die Prozesspfadgenerierung vorgeschlagen.}, language = {de} } @article{BodeEhrlich, author = {Bode, J. and Ehrlich, Ingo}, title = {Entwicklung eines finiten Elements f{\"u}r Sandwichanwendungen}, series = {Zeitschrift f{\"u}r Angewandte Mathematik und Mechanik (ZAMM), Journal of Applied Mathematics and Mechanics}, volume = {77}, journal = {Zeitschrift f{\"u}r Angewandte Mathematik und Mechanik (ZAMM), Journal of Applied Mathematics and Mechanics}, number = {1}, pages = {41 -- 42}, language = {de} } @article{RomanoHoinkesEhrlichetal., author = {Romano, Marco and Hoinkes, Carl J. J. and Ehrlich, Ingo and H{\"o}cherl, Johannes and Gebbeken, Norbert}, title = {Experimental investigation of energy dissipation properties of fibre reinforced plastics with hybrid layups under high-velocity impact loads}, series = {Journal of Achievements in Materials and Manufacturing Engineering (JAMME)}, volume = {64}, journal = {Journal of Achievements in Materials and Manufacturing Engineering (JAMME)}, number = {1}, pages = {14 -- 20}, abstract = {Purpose: The present work deals with the experimental investigation concerning the energy dissipation capacity of different kinds of reinforcement fibres in monolithic and hybrid layups under high velocity impact loads. The investigated kinds of fibres are carbon, glass and basalt. Design/methodology/approach: The test panels have been impregnated with thermoset resin. Curing was done by autoclave processing. In order to obtain comparable fibre volume contents of approx. 60 \% in the different layups (monolithic and hybrid without and with separating layer), curing cycles adapted to the type of layup have been identified. The resulting fibre volume content of the test panels has been determined both by weighing and experimentally by chemical extraction and calcination. The impact load was applied by an instrumented experimental setup. Thereby both commercially available bullets and bearing balls accelerated with weighted propellant in a sabot have been used as impactors. The measured values are the velocities of the bearing balls as the impactor before and after penetration of the test panels. Findings: In both cases the results show the energy dissipation capacity of each single kind of fibre in case of the monolithic layups as well as the enhanced properties of the hybrid stacked layups without and with the separating layer as a core material. Typical failure modes on the impact surface and on the outlet areas are identified. Research limitations/implications: The influence of the respective kind of impactors, namely bullets and bearing balls, on the evaluated results is identified. Thereby the bearing balls exhibited a higher degree of reproducibility due to several reasons. Originality/value: Fibre reinforced plastics with hybrid stacking sequences can be used as load-bearing structures and at the same time as safety structures for passengers in automotive or aerospace applications. Moreover, with the hybrid stacked composites lightweight concepts can efficiently be realized regarding energy saving issues.}, language = {en} } @inproceedings{DinnebierEhrlich, author = {Dinnebier, Heinrich and Ehrlich, Ingo}, title = {The Effects of Severe Temperature Changes and High Humidity on Porous CFRP}, series = {Proceedings of the 15th International Materials Symposium (IMSP´2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014}, booktitle = {Proceedings of the 15th International Materials Symposium (IMSP´2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014}, editor = {Meran, C.}, pages = {433 -- 440}, abstract = {Purpose: A route to manufacture porous carbon fiber reinforced plastic (CFRP) for study purposes is described. Design/methodology/approach: The porous CFRP is characterized using standard techniques such as matrix digestion as well as the more sophisticated method of high resolution Microfocus X-Ray Tomography (μCT). A comparison of the results of those methods is presented. The mass gains of specimens with a wide range of porosity have been measured both in constant humidity and in alternating environments. Findings: It could be shown that severe temperature changes can temporarily increase the moisture content of porous CFRP. However, after the return to a constant environment, the moisture content returns back to saturation levels. Furthermore, it could be shown by X-Ray Tomography that even under severe climatic conditions no permanent liquid water condensates inside the pores. Research limitations/implications: Using Microfocus Computed Tomography it could be shown that even after nearly a year under hot-wet conditions and more than 150 severe temperature cycles there is no liquid water detectable inside the pores. Originality/value: In this paper the effects of severe temperature changes and high humidity on porous CFRP.}, language = {en} } @article{RomanoEhrlichGebbeken, author = {Romano, Marco and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Parametric characterization of a mesomechanic kinematic in plain and twill weave 2/2 reinforced composites by FE-calculations}, series = {Archives of Materials Science and Engineering (ArchivesMSE)}, volume = {97}, journal = {Archives of Materials Science and Engineering (ArchivesMSE)}, number = {1-2}, publisher = {Index Copernicus}, issn = {1897-2764}, doi = {10.5604/01.3001.0013.2869}, pages = {20 -- 38}, abstract = {Purpose: A parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites is investigated by numerical investigations. Design/methodology/approach: Due to the definition of plain representative sequences of balanced plain-weave and twill-weave 2/2 fabric reinforced single layers based on sines the variable geometric parameters are the amplitude and the length of the ondulation. Findings: The mesomechanic kinematic can be observed in the FE analyses for both kinds of fabric constructions. Research limitations/implications: The FE analyses consider elasticity and contraction due to Poisson effects, respectively, of the model under selected longitudinal strains. Practical implications: The results are evaluated at relevant positions on the centre-line of the ondulated warp-yarn of the plain representative model. A direct and linear coupling in case of the transversal kinematic behaviour, and thereby a corresponding definite reduction of the evaluated longitudinal strains in terms of the difference of the applied and determined longitudinal strains is identified. Originality/value: Both characteristic purely kinematic reactions due to geometric constraints directly depend on the introduced degree of ondulation. This non-dimensional parameter relates amplitude and length of one complete ondulation, and thus represents the intensity of the ondulation of the respective fabric construction.}, language = {en} } @article{NiedernhuberHoltmannspoetterEhrlich, author = {Niedernhuber, Michael and Holtmannsp{\"o}tter, Jens and Ehrlich, Ingo}, title = {Fiber-oriented repair geometries for composite materials}, series = {Composites, Part B}, volume = {94}, journal = {Composites, Part B}, doi = {10.1016/j.compositesb.2016.03.027}, pages = {327 -- 337}, abstract = {In this paper, the idea of fiber-oriented repair geometries for carbon fiber reinforced plastics (CFRP) is investigated. It considers the differing mechanical properties of unidirectional fiber reinforced material by excluding overlapping regions perpendicular to the fiber direction of the particular layer. A mechanical and numerical comparison of tensile strength of stepped joints with continuous step lengths per ply and stepped joints with reduced step lengths in plies with fiber orientation differing from load direction is performed. Finite element simulations show similar shear stresses. Mechanical tests of CFRP laminates with stepped joints show no significant deviation in tensile strength, in spite of a joint length reduction of nearly 40\%. This leads to the possibility of a significant reduction of repair area.}, language = {en} } @techreport{PongratzEhrlich, author = {Pongratz, Christian and Ehrlich, Ingo}, title = {High-End-Strukturen f{\"u}r den Leichtbau - mit faserverst{\"a}rktem 3D-Druck}, series = {Forschung 2018 / Ostbayerische Technische Hochschule Regensburg}, journal = {Forschung 2018 / Ostbayerische Technische Hochschule Regensburg}, editor = {Baier, Wolfgang}, organization = {Ostbayerische Technische Hochschule Regensburg}, isbn = {978-3-9818209-4-2}, pages = {64 -- 65}, language = {de} } @inproceedings{ValentinoRomanoEhrlichetal., author = {Valentino, Piergiorgio and Romano, Marco and Ehrlich, Ingo and Furgiuele, Franco and Gebbeken, Norbert}, title = {Mechanical characterization of basalt fibre reinforced plastic with different fabric reinforcements - Tensile tests and FE-calculations with representative volume elements (RVEs)}, series = {Acta Fracturae - XXll Convegno Nazionale IGF (Italiano Gruppo Frattura)}, booktitle = {Acta Fracturae - XXll Convegno Nazionale IGF (Italiano Gruppo Frattura)}, editor = {Iacovello, F. and Risitano, G. and Susmel, L.}, abstract = {This paper describes the results of tensile tests and finite element (FE) calculations with representative volume elements (RVEs) of basalt fibre reinforced plastic with two different types of fabric reinforcements. As fabric reinforcements show repeating ondulations of warp and fill yarn, simple mixtures laws reach their limits. That is the reason why the mesoscopic dimension, lying between the microscopic and the macroscopic dimension, has to be taken into account when a mechanical characterization of fabric reinforced composites is carried out. The aim of this work is to determine the stiffness of a fabric reinforced composite in warp and fill direction with numerical investigations. The simulations are based on FE-calculation with two different RVEs. The tensile tests and the FE-calculations have been carried out for two different types of basalt fabrics, namely twill 2/2 and twill 1/3. The comparison between the experimental data and the results of the FE-calculations are provided in order to support the validity of the proposed model.}, language = {en} } @techreport{ValentinoRomanoEhrlichetal., author = {Valentino, Piergiorgio and Romano, Marco and Ehrlich, Ingo and Furgiuele, Franco and Gebbeken, Norbert}, title = {Mechanische Charakterisierung von basaltfaser-verst{\"a}rkten Kunststoffen mit Gewebeverst{\"a}rkung - Numerische und experimentelle Untersuchungen}, series = {Forschungsbericht 2013}, journal = {Forschungsbericht 2013}, publisher = {inixmedia GmbH Marketing \& Medienberatung}, organization = {Ostbayerische Technische Hochschule Regensburg}, language = {de} } @inproceedings{OttawaRomanoEhrlichetal., author = {Ottawa, Patrycja and Romano, Marco and Ehrlich, Ingo and Wagner, Marcus and Gebbeken, Norbert}, title = {The influence of ondulation in fabric reinforced composites on dynamic properties in a mesoscopic scale}, series = {11. LS-DYNA Forum, 9. - 10. Oktober 2012, Ulm}, booktitle = {11. LS-DYNA Forum, 9. - 10. Oktober 2012, Ulm}, pages = {171 -- 172}, abstract = {Structural mechanic properties of fiber reinforced plastics depend on the single components' properties, namely matrix and fiber [5]. Simple micromechanic homogenization theories reach a limit when a laminate consists of fabric reinforced layers instead of unidirectional layers. The ondulations of warp and fill yarn caused by the textile semi-finished product are the reason why the mesoscopic scale, which is in between the microscopic and the macroscopic scale, has to be taken into account when mechanically characterizing fabric reinforced composites [3]. In this scale a mesomechanic kinematic can be derived analytically. Especially, when considering free damped vibrations of structures the repeated acting of the kinematic correlation significantly affects the damping behaviour to higher values compared to theoretically predicted damping ratios. The model is investigated using Finite-Element-Analyses and basically validated experimentally.}, language = {en} } @article{SchimmerLadewigMotschetal., author = {Schimmer, Florian and Ladewig, Sven and Motsch, Nicole and Hausmann, Joachim M. and Ehrlich, Ingo}, title = {Comparison of Low-Velocity Impact Damage Behavior of Unidirectional Carbon Fiber-Reinforced Thermoset and Thermoplastic Composites}, series = {Key Engineering Materials}, volume = {809}, journal = {Key Engineering Materials}, publisher = {Trans Tech Publications}, issn = {1662-9795}, doi = {10.4028/www.scientific.net/KEM.809.9}, pages = {9 -- 14}, abstract = {This paper investigates the damage behavior of thermoset and thermoplastic fiber-reinforced composites. The specimens were subjected to low-velocity impacts (LVI) to produce barely visible impact damages (BVID). To compare the dependency of the matrix system and the laminate lay-up on the impact damage, four test series were set up. Therefore, laminates with an epoxy (EP) and a polyether ether ketone (PEEK) matrix in a quasi-isotropic (QI) [+45/0/-45/90]2s and an orthotropic (OT) fiber lay-up [0/90]4s were manufactured. To eliminate the influence of variant fiber systems, the thermoplastic tape and the thermoset prepreg contain similar carbon fibers (CF). After impact testing with three different impact energies, inner damages were investigated by using ultrasonic analyses. To get a deeper understanding of the interior damage mechanisms, cross sections of the damaged areas were examined via reflected light microscopy. By using these destructive and non-destructive test methods, significant differences in the damage behavior of composites with thermoplastic and thermoset matrix systems were identified for both laminate lay-ups.}, language = {en} } @article{KastenmeierSchmidEhrlichetal., author = {Kastenmeier, Andreas and Schmid, Vinzent and Ehrlich, Ingo and Petratos, P. and Mourtos, N. and Trafalis, T.}, title = {Specimen Preparation and Material Characterization of Filament Wound GFRP Composite Tubes}, series = {Athens Journal of Technology \& Engineering}, volume = {4}, journal = {Athens Journal of Technology \& Engineering}, number = {3}, pages = {191 -- 205}, abstract = {Filament wound composite structures are widely used in the field of pressure vessels, tubes, pipelines or rocket cases. The mechanical behavior of these structures is typically different from those of flat laminated structures due to an alternating lay-up sequence, winding tension and manufacturing induced imperfections. However, design and analysis issues require the same engineering data as used for laminated structures in general. It has therefore become necessary to establish an accompanying quality assurance procedure following the production process to identify the material properties of the manufactured tubes especially for the single layer. Consequently, there are three different approaches of determining the elastic moduli and tensile strengths of a filament wound laminate. Either specimens are resected from a curved tube, from a tube with plane areas or standardized flat specimens are manufactured under deviating production conditions. All approaches entail disadvantages, whether in terms of manufacturing or testing parameters including geometry, lay-up sequence, porosity, fiber tension and load direction. This study presents the discrepancies in the determination of mechanical properties of a filament wound glass-fiber-reinforced polymer tube on curved or cylindrical specimens and flat specimens produced to meet the specifications of international standards. In order to obtain material properties not only in longitudinal but also in transverse direction of the tubes, the so-called split-disk tensile test modeled after ASTM Standard D 2290, is used with tube segments.The procedures of specimen production and preparation are described in detail. Material properties such as the fiber volume and void content of the composite specimens are conducted in order to consider quality and production differences. Finally tensile tests are performed and the results are compared and discussed.}, language = {en} } @article{RomanoEhrlichGebbeken, author = {Romano, Marco and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Structural mechanic material damping in fabric reinforced composites}, series = {Archives of Materials Science and Engineering (ArchivesMSE)}, volume = {88}, journal = {Archives of Materials Science and Engineering (ArchivesMSE)}, number = {1}, doi = {10.5604/01.3001.0010.7747}, pages = {12 -- 41}, abstract = {Purpose: A review regarding the acting mechanisms of structural dynamic material damping in fabric reinforced composites is presented. Design/methodology/approach: Mechanical acting principles identified by different investigations are considered. Aspects of the determination and calculation of structural mechanical material properties of fabric reinforced composites are described. Approaches intending the description and classification of ondulations in fabrics reinforced single layers are demonstrated. Findings: The mesomechanic geometry of fabrics is not considered sufficiently by relatively simple homogenization approaches. Yet, it significantly affects its structural dynamic material properties, especially the dynamic ones. Research limitations/implications: In each case the different damping mechanisms act coupled and occur at the same time. Therefore a separation procedure is required in any case. Practical implications: Against the background of the comparison and remarks of the presented papers a reasonable further procedure is recommended. Thereby, FE-calculations with a parametrical variation of the mesomechanic geometry in order to identify kinematic correlations due to geometric constraints are suggested. Originality/value: The idea of the representation of the geometric conditions in terms of a degree of ondulation is described. Such a non-dimensional specific value representing the intensity of the ondulation would enable the comparability of the results of different kinds of investigations.}, language = {en} } @article{BohmannSchlampEhrlich, author = {Bohmann, T. and Schlamp, Matthias and Ehrlich, Ingo}, title = {Acoustic emission of material damages in glass fibre-reinforced plastics}, series = {Composites Part B: Engineering}, volume = {155}, journal = {Composites Part B: Engineering}, number = {December}, publisher = {Elsevier}, doi = {10.1016/j.compositesb.2018.09.018}, pages = {444 -- 451}, abstract = {The aim of this study is to compare two different standardized testing procedures, tensile testing and Mode-I double cantilever beam (DCB) testing, to evaluate a possible correlation between the dominant failure in glass fibre-reinforced plastics and their according acoustic emissions (AE). AE is processed by using a burst collection of all recorded transient signals and is further analysed with the k-means clustering algorithm. To generate damage related AE, a series of experiments for tensile testing and Mode-I DCB testing is performed on 16-layer glass fibre/epoxy specimens with a cross-ply lay-up for tensile and an unidirectional lay-up for Mode-I DCB testing. Three sensors at tensile testing and one sensor at Mode-I DCB testing gather AE data. The results of clustered burst signals show a good accordance between both testing procedures, with a similar weighted peak frequency (WPF) range in each classified cluster. In total, three different clusters are determined. An assignment of these three clusters to the three dominant damage mechanisms, visually observed by microscopy, is suggested.}, language = {en} } @article{DinnebierEhrlich, author = {Dinnebier, Heinrich and Ehrlich, Ingo}, title = {The effects of severe temperature changes and high humidity on porous CFRP}, series = {Journal of Achievements in Materials and Manufacturing Engineering (JAMME)}, volume = {67}, journal = {Journal of Achievements in Materials and Manufacturing Engineering (JAMME)}, number = {1}, pages = {14 -- 20}, abstract = {Purpose: A route to manufacture porous carbon fiber reinforced plastic (CFRP) for study purposes is described. Design/methodology/approach: The porous CFRP is characterized using standard techniques such as matrix digestion as well as the more sophisticated method of high resolution Microfocus X-Ray Tomography (μCT). A comparison of the results of those methods is presented. The mass gains of specimens with a wide range of porosity have been measured both in constant humidity and in alternating environments. Findings: It could be shown that severe temperature changes can temporarily increase the moisture content of porous CFRP. However, after the return to a constant environment, the moisture content returns back to saturation levels. Furthermore, it could be shown by X-Ray Tomography that even under severe climatic conditions no permanent liquid water condensates inside the pores. Research limitations/implications: Using Microfocus Computed Tomography it could be shown that even after nearly a year under hot-wet conditions and more than 150 severe temperature cycles there is no liquid water detectable inside the pores. Originality/value: In this paper the effects of severe temperature changes and high humidity on porous CFRP.}, language = {en} } @article{RomanoHoinkesEhrlichetal., author = {Romano, Marco and Hoinkes, Carl J. J. and Ehrlich, Ingo and H{\"o}cherl, Johannes and Gebbeken, Norbert}, title = {Experimental investigation of fibre reinforced plastics with hybrid layups under high-velocity impact loads}, series = {Frattura ed Integrit{\`a} Strutturale (Fracture and Structural Integrity)}, volume = {8}, journal = {Frattura ed Integrit{\`a} Strutturale (Fracture and Structural Integrity)}, number = {29}, doi = {10.3221/IGF-ESIS.29.34}, pages = {384 -- 398}, abstract = {This paper deals with experimental investigations concerning energy dissipation capacity of different kinds of reinforcement fibres in monolithic and hybrid layups under high-velocity impact loads. The investigated kinds of fibres are carbon, glass and basalt fibres. Therefore test panels, using the same thermoset resin, were built up and cured by autoclave processing. The fibre volume content of the test panels has been determined. Furthermore the influence of a separating layer at selected positions in the hybrid stacked panels was investigated. The results show the influence and the energy dissipation capacity of each single kind of fibre and the enhanced properties for the hybrid layups by hybrid stacking sequences and the use of a separating core material.}, language = {en} } @techreport{EisenriedRomanoJungbaueretal., author = {Eisenried, Michael and Romano, Marco and Jungbauer, Bastian and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Herstellung von unidirektional verst{\"a}rkten Prepregs im Labormaßstab - Einfluss von Fertigungsparametern auf die Materialqualit{\"a}t}, series = {Forschungsbericht 2013 / Ostbayerische Technische Hochschule Regensburg}, journal = {Forschungsbericht 2013 / Ostbayerische Technische Hochschule Regensburg}, address = {Regensburg}, pages = {51 -- 52}, language = {de} } @article{PongratzSchlampJungbaueretal., author = {Pongratz, Christian and Schlamp, Matthias and Jungbauer, Bastian and Ehrlich, Ingo and Petratos, P. and Mourtos, N.}, title = {Detection of Delamination Damages in Thin Composite Plates using Noncontact Measurement of Structural Dynamic Behavior}, series = {Athens Journal of Technology \& Engineering}, volume = {3}, journal = {Athens Journal of Technology \& Engineering}, number = {4}, doi = {10.30958/AJTE.3-4-3}, pages = {315 -- 331}, language = {en} } @techreport{PongratzEhrlich, author = {Pongratz, Christian and Ehrlich, Ingo}, title = {DampSIM: Lebensdauer{\"u}berwachung von faserverst{\"a}rkten Kunststoffen auf Basis der strukurdynamischen Werkstoffd{\"a}mpfung}, series = {Forschungsbericht 2017 / Ostbayerische Technische Hochschule Regensburg}, journal = {Forschungsbericht 2017 / Ostbayerische Technische Hochschule Regensburg}, editor = {Baier, Wolfgang}, organization = {Ostbayerische Technische Hochschule Regensburg}, isbn = {978-3-9818209-3-5}, pages = {62 -- 63}, language = {de} } @inproceedings{RomanoHoinkesEhrlichetal., author = {Romano, Marco and Hoinkes, Carl J. J. and Ehrlich, Ingo and H{\"o}cherl, J. and Gebbeken, Norbert}, title = {Influence of the impactor on the experimentally determined energy dissipation properties of fiber-reinforced plastics with hybrid layups under high velocity impact loads}, series = {Proceeding of the 15th International Materials Symposium (IMSP´2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014}, booktitle = {Proceeding of the 15th International Materials Symposium (IMSP´2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014}, editor = {Meran, C.}, pages = {650 -- 664}, language = {en} } @inproceedings{EhrlichDinnebierJost, author = {Ehrlich, Ingo and Dinnebier, Heinrich and Jost, C.}, title = {Comparison of Impact Delaminations in CFRP Using Ultrasonic Testing, Microfocus Computed X-Ray Tomography and Micrographic Cross-Section}, series = {Proceeding of the 15th International Materials Symposium (IMSP´2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014}, booktitle = {Proceeding of the 15th International Materials Symposium (IMSP´2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014}, editor = {Meran, C.}, pages = {441 -- 450}, language = {en} } @article{RomanoMicklitzOlbrichetal., author = {Romano, Marco and Micklitz, Matthias and Olbrich, Florian and Bierl, Rudolf and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Experimental investigation of damping properties of unidirectionally and fabric reinforced plastics by the free decay method}, series = {Journal of Achievements in Materials and Manufacturing Engineering}, volume = {63}, journal = {Journal of Achievements in Materials and Manufacturing Engineering}, number = {2}, pages = {65 -- 80}, abstract = {Purpose: of this paper is experimental investigation of damping properties of unidirectionally and fabric reinforced plastics by the free decay method. Design/methodology/approach: For the evaluation of the presumed effect experimental structural dynamic investigations comparing unidirectionally and fabric reinforced plastics are carried out. In detail the free decay behaviour of flat beamlike specimens under fixed-free boundary conditions and relatively constant and reproducible displacement excitation is investigated. Findings: The vibrating structure has been measured by a laser scanning vibrometer PSV 400 from POLYTEC. In both cases evaluation of the results yields enhanced damping properties of the specimens with fabric reinforcement compared to the unidirectionally reinforced specimens. The results justify the presumed acting of a mesomechanic kinematic. Research limitations/implications: The results show that in either case the material damping in terms of the logarithmic decrement of the fabric reinforced material is higher than the material damping in of the unidirectionally reinforced material. Additionally, when the fabric reinforced specimens are addressed, in each case the plain weave reinforced specimens exhibited higher values of the material damping as the twill weave 2/2 reinforced ones. Originality/value: Ondulations in fabrics as a textile semi-finished product are caused by the alternating crossing of warp and fill yarns. In the mesoscopic scale the acting of a mesomechanic kinematic is presumed to enhance the damping properties under cyclic elastic deformation. For the evaluation of the presumed effect experimental structural dynamic investigations comparing unidirectionally and fabric reinforced plastics are carried out.}, language = {en} } @techreport{SchlampEhrlich, author = {Schlamp, Matthias and Ehrlich, Ingo}, title = {Analyse des Impact-Verhaltens gekr{\"u}mmter Strukturbauteile von Luftfahrzeugen zur Entwicklung eines Struktur{\"u}berwachungssystems f{\"u}r faserverst{\"a}rkte Kunststoffe - BIRD}, series = {Forschung 2019 / Ostbayerische Technische Hochschule Regensburg}, journal = {Forschung 2019 / Ostbayerische Technische Hochschule Regensburg}, editor = {Baier, Wolfgang}, publisher = {VMK Verlag f{\"u}r Marketing \& Kommunikation GmbH \& Co. KG}, organization = {Ostbayerische Technische Hochschule Regensburg}, isbn = {978-3-9818209-6-6}, pages = {40 -- 41}, abstract = {Die in Flugvorausrichtung weisenden Bauteile von Luftfahrzeugen sind oftmals durch Einschl{\"a}ge aufgrund von Vogelschlag, Hagel oder aufgewirbelten Kleinteilen gef{\"a}hrdet. Diese Einschl{\"a}ge, sogenannte Impacts, weisen bei faserverst{\"a}rkten Kunststoffen ein stark kr{\"u}mmungs- und materialabh{\"a}ngiges Verhalten und Schadensausmaß auf. Impact-Sch{\"a}digungen f{\"u}hren oftmals zu hohen Reparaturkosten, welche durch eine genauere Kenntnis des Schadens verringert werden k{\"o}nnen. Zur Klassifizierung dieser Sch{\"a}digungen steht dabei vor allem das auftretende Frequenz signal des Impacts im Fokus der Untersuchungen.}, language = {de} } @techreport{SieglEhrlich, author = {Siegl, Marco and Ehrlich, Ingo}, title = {Internationale Forschung zum Biege- und Deformationsverhalten von faserverst{\"a}rkten Kunststoffrohren}, series = {Forschung 2019 / OTH Regensburg}, journal = {Forschung 2019 / OTH Regensburg}, editor = {Baier, Wolfgang}, publisher = {VMK Verlag f{\"u}r Marketing \& Kommunikation}, organization = {Ostbayerische Technische Hochschule Regensburg}, isbn = {978-3-9818209-6-6}, pages = {42 -- 43}, language = {de} } @inproceedings{RomanoMicklitzOlbrichetal., author = {Romano, Marco and Micklitz, Matthias and Olbrich, Florian and Bierl, Rudolf and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Experimental investigation of damping properties of unidirectionally and fabric reinforces plastics by the free decay method}, series = {Proceeding of the 15th International Materials Symposium (IMSP´2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014}, booktitle = {Proceeding of the 15th International Materials Symposium (IMSP´2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014}, pages = {665 -- 679}, language = {en} } @inproceedings{JudenmannHoltmannspoetterEhrlich, author = {Judenmann, Anna and Holtmannsp{\"o}tter, Jens and Ehrlich, Ingo}, title = {Additive Manufacturing of Continuous Fiber-Reinforced Composites}, series = {Proceedings of the Munich Symposium on Lightweight Design 2022}, booktitle = {Proceedings of the Munich Symposium on Lightweight Design 2022}, language = {de} } @misc{SchimmerGebhardtMotschEichmannetal., author = {Schimmer, F. and Gebhardt, Jakob and Motsch-Eichmann, N. and Hausmann, Joachim M. and Ehrlich, Ingo}, title = {The effect of curvature on the low-velocity impact resistance of CF/PEEK laminates}, series = {30 Years IVW Anniversary Colloquium, Leibnitz-Institut f{\"u}r Verbundwerkstoffe Kaiserslautern, 2021}, journal = {30 Years IVW Anniversary Colloquium, Leibnitz-Institut f{\"u}r Verbundwerkstoffe Kaiserslautern, 2021}, language = {en} } @phdthesis{Ehrlich, author = {Ehrlich, Ingo}, title = {Impactverhalten schwach gekr{\"u}mmter Strukturen aus faserverst{\"a}rkten Kunststoffen}, address = {M{\"u}nchen}, language = {de} } @article{GebhardtSchlampEhrlichetal., author = {Gebhardt, Jakob and Schlamp, M. and Ehrlich, Ingo and Hiermaier, Stefan}, title = {Low-velocity impact behavior of elliptic curved composite structures}, series = {International Journal of Impact Engineering}, volume = {180}, journal = {International Journal of Impact Engineering}, publisher = {Elsevier}, doi = {10.1016/j.ijimpeng.2023.104663}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-59304}, pages = {8}, abstract = {Although many composite structures are inconsistently curved, such as the leading edges of aircraft wings, the variety of research in impact engineering is almost limited to the impact performance of plates or cylindrically curved specimens. It is not known whether the findings obtained from standardized tests can be transferred to curved structures or which adaptions are required. Therefore, a deeper understanding of the deformation and damage behavior of inconsistently curved structures is essential to transfer the observed impact behavior of flat specimens to general curved structures and therefore to utilize the full lightweight potential of a load-specific design. An accurate description of the procedure as well as the results of the experimental and numerical study of the low-velocity impact behavior of differently single-curved elliptic specimens is presented. To close the research gap of the impact behavior of geometries with curvatures between the plates and simplified leading edges, novel specimens geometries have been derived from established impact test standards. Glassfiber-reinforced specimens are subjected to an instrumented impact test at constant impact energy. This is numerically investigated by a stacked-layer model, which used cohesive zone modeling to enable the simulation of matrix cracking, fiber fracture and delamination. The resulting projected damage areas, as well as the force and deflection histories, were evaluated and section cuts were examined to discuss the damage morphology, formation and propagation process. Significant effects on maximum deflection, compliance and dynamic behavior on the size and morphology of damage were found.}, language = {en} } @inproceedings{SchmidJungbauerRomanoetal., author = {Schmid, Vinzent and Jungbauer, Bastian and Romano, Marco and Ehrlich, Ingo and Gebbeken, Norbert}, title = {The influence of different types of fabrics on the fibre volume content and porosity in basalt fibre reinforced plastics}, series = {2nd Applied Research Conference 2012 - ARC 25./26. June 2012}, booktitle = {2nd Applied Research Conference 2012 - ARC 25./26. June 2012}, editor = {Mottok, J{\"u}rgen and Ziemann, Olaf}, publisher = {Shaker}, pages = {162 -- 165}, abstract = {High quality semi-finished products with reproducible properties of basaltic fibres are hardly available on the market. In order to examine the properties of basalt fibre reinforced plastics high quality specimens are necessary. The fibre volume content and the porosity of the produced specimen are used as the typical criteria to evaluate the achieved quality of the produced material. The effect of the geometrical properties of the different semi-finished products on the fibre volume contents is relatively small whereas the porosity content is considerably affected.}, language = {en} } @inproceedings{LadewigSieglEhrlich, author = {Ladewig, Sven and Siegl, Marco and Ehrlich, Ingo}, title = {Discussion about Viscosity Theories for Fibre-Reinforced Thermoplastics}, series = {Applied Research Conference 2018 - ARC 2018, 10 July, Deggendorf}, booktitle = {Applied Research Conference 2018 - ARC 2018, 10 July, Deggendorf}, editor = {Mottok, J{\"u}rgen and Reichenberger, Marcus and Bogner, Werner}, publisher = {Pro Business Verlag}, address = {Berlin}, pages = {144 -- 149}, abstract = {The effect of process variables such as shear rate and temperature on the viscosity of polypropylene during the processing of thermoplastic based composites was investigated in this study. The melt impregnation is used in the process of continuous glass fibre reinforced thermoplastic composites. To develop a mathematical model for roving impregnation, it's essential to know about the viscous behaviour of the matrix system. Therefore, this paper will discuss rheological models to describe these phenomena, based on the gathered viscosity data from the partner laboratory at the University of West Bohemia in Pilsen.}, language = {en} } @inproceedings{SteinmannEhrlich, author = {Steinmann, Sven and Ehrlich, Ingo}, title = {Investigation of transverse impact stress in fiber reinforced plastics under high-velocity impact and determination of the experimental procedure}, series = {Applied Research Conference 2016 - ARC 2016, Augsburg, 24 June 2016}, booktitle = {Applied Research Conference 2016 - ARC 2016, Augsburg, 24 June 2016}, editor = {Mottok, J{\"u}rgen and Reichenberger, Marcus and Stolle, Reinhard}, publisher = {Pro Business Verlag}, address = {Berlin}, language = {en} } @inproceedings{SchmidJungbauerRomanoetal., author = {Schmid, Vinzent and Jungbauer, Bastian and Romano, Marco and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Diminution of mass of different types of fibre reinforcements due to thermal load}, series = {Applied Research Conference 2012 - ARC 2012, 25./26. June 2012}, booktitle = {Applied Research Conference 2012 - ARC 2012, 25./26. June 2012}, editor = {Mottok, J{\"u}rgen and Ziemann, Olaf}, publisher = {Shaker}, pages = {231 -- 235}, language = {en} } @inproceedings{BohmannSchlampEhrlich, author = {Bohmann, T. and Schlamp, Matthias and Ehrlich, Ingo}, title = {Analysis of the Acoustic Emission Failure Frequencies of Glass Fiber Reinforced Composite Components}, series = {Applied Research Conference 2017 - ARC, 7 July 2017, M{\"u}nchen}, booktitle = {Applied Research Conference 2017 - ARC, 7 July 2017, M{\"u}nchen}, editor = {Klippel, Clemens and Mottok, J{\"u}rgen and Reichenberger, Marcus}, publisher = {Book-on-demand Verlag}, address = {Norderstedt}, pages = {369 -- 373}, language = {en} } @inproceedings{NueblerSchmidEhrlich, author = {N{\"u}bler, S. and Schmid, Vinzent and Ehrlich, Ingo}, title = {FEM-Simulation of a Tube to Flange Joint under Bending Load}, series = {Applied Research Conference 2016 - ARC 2016, Augsburg, 24 June 2016}, booktitle = {Applied Research Conference 2016 - ARC 2016, Augsburg, 24 June 2016}, editor = {Mottok, J{\"u}rgen and Reichenberger, Marcus and Stolle, Reinhard}, publisher = {Pro Business Verlag}, address = {Berlin}, language = {en} } @inproceedings{HoinkesRomanoEhrlichetal., author = {Hoinkes, C. and Romano, Marco and Ehrlich, Ingo and H{\"o}cherl, J. and Gebbeken, Norbert}, title = {Investigation of fibre reinforced plastics with monolithic and hybrid stacking sequences under high-velocity impact loads}, series = {Applied Research Conference 2014 - ARC 2014, 5th July 2014, Ingolstadt}, booktitle = {Applied Research Conference 2014 - ARC 2014, 5th July 2014, Ingolstadt}, editor = {Ziemann, Olaf and Mottok, J{\"u}rgen and Pforr, Johannes}, publisher = {Shaker}, address = {Aachen}, language = {en} } @inproceedings{PongratzEhrlich, author = {Pongratz, Christian and Ehrlich, Ingo}, title = {Structural Dynamic Analysis of Thin Composite Plates Using Noncontact Measurement and Excitation}, series = {Applied Research Conference 2016 - ARC 2016, Augsburg, 24 June 2016}, booktitle = {Applied Research Conference 2016 - ARC 2016, Augsburg, 24 June 2016}, editor = {Mottok, J{\"u}rgen and Reichenberger, Marcus and Stolle, Reinhard}, publisher = {Pro Business Verlag}, address = {Berlin}, isbn = {978-3-86460-494-2}, pages = {351 -- 358}, language = {en} } @inproceedings{BaumerKastenmeierEhrlich, author = {Baumer, A. and Kastenmeier, Andreas and Ehrlich, Ingo}, title = {Investigation of Bolted Composite Joints with Different Reinforcement Elements at the Bolt Hole}, series = {4th Applied Research Conference, 5th July 2014, Ingolstadt}, booktitle = {4th Applied Research Conference, 5th July 2014, Ingolstadt}, editor = {Ziemann, Olaf and Mottok, J{\"u}rgen and Pforr, Johannes}, publisher = {Shaker}, pages = {255 -- 258}, language = {en} } @inproceedings{FritzSchmidEhrlich, author = {Fritz, B. and Schmid, Vinzent and Ehrlich, Ingo}, title = {Analytical and numerical shear stress analysis of adhesive structural bonded joints under tension load}, series = {Applied Research Conference 2014 - ARC 2014, 5th July 2014, Ingolstadt}, booktitle = {Applied Research Conference 2014 - ARC 2014, 5th July 2014, Ingolstadt}, editor = {Ziemann, Olaf and Mottok, J{\"u}rgen and Pforr, Johannes}, publisher = {Shaker}, address = {Aachen}, pages = {266 -- 271}, language = {de} } @inproceedings{BaumerKastenmeierEhrlich, author = {Baumer, A. and Kastenmeier, Andreas and Ehrlich, Ingo}, title = {A Numerical Study of Reinforced Bolted Composite Joints}, series = {Applied Research Conference 2015: ARC 2015 - N{\"u}rnberg, 3rd July 2015}, booktitle = {Applied Research Conference 2015: ARC 2015 - N{\"u}rnberg, 3rd July 2015}, editor = {Mottok, J{\"u}rgen and Reichenberger, Marcus and Scharfenberg, J. and Ziemann, Olaf}, publisher = {Book-on-demand-Verlag}, pages = {278 -- 282}, language = {en} } @inproceedings{WaetzigSchmidEhrlich, author = {W{\"a}tzig, A. and Schmid, Vinzent and Ehrlich, Ingo}, title = {Damage Modelling of Adhesive Joints Using the Cohesive Zone Model}, series = {Applied Research Conference 2016 - ARC 2016, Augsburg, 24 June 2016}, booktitle = {Applied Research Conference 2016 - ARC 2016, Augsburg, 24 June 2016}, editor = {Mottok, J{\"u}rgen and Reichenberger, Marcus and Stolle, Reinhard}, publisher = {Pro Business Verlag}, address = {Berlin}, language = {en} } @inproceedings{EisenriedRomanoJungbaueretal., author = {Eisenried, Michael and Romano, Marco and Jungbauer, B. and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Influence of parameters of the production process on the material quality of unidirectionally reinforced prepregs}, series = {Applied Research Conference 2013, ARC 2013 ; 17th and 18th October 2013, Deggendorf}, booktitle = {Applied Research Conference 2013, ARC 2013 ; 17th and 18th October 2013, Deggendorf}, editor = {Ziemann, Olaf and Bogner, Werner and Mottok, J{\"u}rgen}, publisher = {Shaker}, address = {Aachen}, pages = {70 -- 75}, language = {en} } @article{MicklitzRomanoEhrlichetal., author = {Micklitz, Matthias and Romano, Marco and Ehrlich, Ingo and Gebbeken, Norbert}, title = {The influence of ondulations in fabric reinforced layers on the damping properties of fibre-reinforced plastics}, series = {Applied Research Conference 2014 - ARC 2014, 5th July 2014, Ingolstadt}, journal = {Applied Research Conference 2014 - ARC 2014, 5th July 2014, Ingolstadt}, editor = {Ziemann, Olaf and Mottok, J{\"u}rgen and Pforr, Johannes}, publisher = {Shaker}, address = {Aachen}, pages = {306 -- 310}, language = {de} } @inproceedings{FaberKastenmeierEhrlich, author = {Faber, M. and Kastenmeier, Andreas and Ehrlich, Ingo}, title = {Three-dimensional finite element analysis of a composite tube with multi-row bolted joints}, series = {Applied Research Conference 2016 - ARC 2016, Augsburg, 24 June 2016}, booktitle = {Applied Research Conference 2016 - ARC 2016, Augsburg, 24 June 2016}, editor = {Mottok, J{\"u}rgen and Reichenberger, Marcus and Stolle, Reinhard}, publisher = {Pro Business Verlag}, address = {Berlin}, language = {de} } @inproceedings{NiedernhuberEhrlichHoltmannspoetter, author = {Niedernhuber, M. and Ehrlich, Ingo and Holtmannsp{\"o}tter, Jens}, title = {Fiber-Oriented Repair of Fiber Reinforced Plastics: Investigations on Tensile Specimens}, series = {4th Applied Research Conference - ARC 2014, 5th July 2014, Ingolstadt}, booktitle = {4th Applied Research Conference - ARC 2014, 5th July 2014, Ingolstadt}, editor = {Ziemann, Olaf and Mottok, J{\"u}rgen and Pforr, Johannes}, publisher = {Shaker}, address = {Aachen}, pages = {298 -- 302}, language = {en} } @inproceedings{NiebauerSchmidEhrlich, author = {Niebauer, M. and Schmid, Vinzent and Ehrlich, Ingo}, title = {Failure Criteria of Adhesively Bonded Joints}, series = {Applied Research Conference 2015 - ARC 2015, N{\"u}rnberg, 3rd July 2015 - 16. Juli 2015}, booktitle = {Applied Research Conference 2015 - ARC 2015, N{\"u}rnberg, 3rd July 2015 - 16. Juli 2015}, editor = {Mottok, J{\"u}rgen and Reichenberger, Marcus and Scharfenberg, J. and Ziemann, Olaf}, publisher = {Pro Business Verlag}, address = {Berlin}, isbn = {978-3863869458}, pages = {347 -- 351}, language = {en} } @inproceedings{IbanezGomezKastenmeierEhrlich, author = {Ibanez Gomez, D. and Kastenmeier, Andreas and Ehrlich, Ingo}, title = {Development and construction of a winding machine for the production of composite tubes}, series = {4th Applied Research Conference - ARC 2014, 5th July 2014, Ingolstadt}, booktitle = {4th Applied Research Conference - ARC 2014, 5th July 2014, Ingolstadt}, editor = {Ziemann, Olaf and Mottok, J{\"u}rgen and Pforr, Johannes}, publisher = {Shaker}, address = {Aachen}, pages = {315 -- 318}, language = {en} } @inproceedings{BrulandSchmidEhrlich, author = {Bruland, Matthias and Schmid, Vinzent and Ehrlich, Ingo}, title = {Analyzing and Testing of a Single Solution of Self-cutting Thread Inserts in Composites}, series = {Applied Research Conference 2014 - ARC 2014, 5th July 2014, Ingolstadt}, booktitle = {Applied Research Conference 2014 - ARC 2014, 5th July 2014, Ingolstadt}, editor = {Ziemann, Olaf and Mottok, J{\"u}rgen and Pforr, Johannes}, publisher = {Shaker}, pages = {286 -- 288}, language = {en} } @article{PongratzTixWolfrumetal., author = {Pongratz, Christian and Tix, Janek and Wolfrum, Johannes and Gerke, Steffen and Ehrlich, Ingo and Br{\"u}nig, Michael}, title = {Test Setup for Investigating the Impact Behavior of Biaxially Prestressed Composite Laminates}, series = {Experimental Techniques}, journal = {Experimental Techniques}, publisher = {Springer Nature}, issn = {0732-8818}, doi = {10.1007/s40799-024-00701-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-70355}, pages = {14 S.}, abstract = {Instrumented impact testing and compression-after-impact testing are important to adequately qualify material behavior and safely design composite structures. However, the stresses to which fiber-reinforced plastic components are typically subjected in practice are not considered in the impact test methods recommended in guidelines or standards. In this paper, a test setup for investigating the impact behavior of composite specimens under plane uniaxial and biaxial preloading is presented. For this purpose, a special test setup consisting of a biaxial testing machine and a specially designed drop-weight tower was developed. The design decisions were derived from existing guidelines and standards with the aim of inducing barely visible impact damage in laminated carbon fiber-reinforced plastic specimens. Several measurement systems have been integrated into the setup to allow comprehensive observation of the impact event and specimen behavior. A feasibility test was performed with biaxially prestressed carbon fiber-reinforced plastic specimens in comparison with unstressed reference tests. The compressive-tensile prestressing resulted in lower maximum contact forces, higher maximum deflections, higher residual deflections and a different damage pattern, which was investigated by light microscopic analysis. Finally, the functionality of the experimental setup is discussed, and the results seem to indicate that the test setup and parameters were properly chosen to investigate the effect of prestresses on the impacts behavior of composite structures, in particular for barely visible subsequent damages.}, subject = {Faserverbundwerkstoff}, language = {en} } @article{KastenmeierSieglEhrlichetal., author = {Kastenmeier, Andreas and Siegl, Marco and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Review of elasto-static models for three-dimensional analysis of thick-walled anisotropic tubes}, series = {Journal of Composite Materials}, journal = {Journal of Composite Materials}, publisher = {Sage}, doi = {10.1177/00219983231215863}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-67521}, abstract = {Most shell or beam models of anisotropic tubes under bending have no validity for thick-walled structures. As a result, the need to develop three-dimensional formulations which allow a change in the stress, strain and displacement distributions across the radial component arises. Basic formulations on three-dimensional anisotropic elasticity were made either stressor displacement-based by Lekhnitskii or Stroh on plates. Lekhnitskii also was the first to expand these analytical formulations to tubes under various loading conditions. This paper presents a review of the stress and strain analysis of tube models using three-dimensional anisotropic elasticity. The focus lies on layered structures, like fiber-reinforced plastics, under various bending loads, although the basic formulations and models regarding axisymmetric loads are briefly discussed. One section is also dedicated to the determination of an equivalent bending stiffness of tubes.}, language = {en} } @unpublished{SieglJungbauerGebhardtetal., author = {Siegl, Marco and Jungbauer, Bastian and Gebhardt, Jakob and Judenmann, Anna and Ehrlich, Ingo}, title = {Winding process of fibre-reinforced thermoplastic tubes with integrated tape production through in-situ roving impregnation and infrared consolidation}, series = {International Journal of Advanced Manufacturing Technology}, journal = {International Journal of Advanced Manufacturing Technology}, doi = {10.21203/rs.3.rs-4085105/v1}, abstract = {The present paper takes a novel approach to production of fibre-reinforced thermoplastic tubes. The method begins with the raw materials, reinforcing fibre and thermoplastic granulate which are processed to tapes through a newly developed direct impregnation process. It is followed by consolidation of fibre-reinforced thermoplastic tubes using infrared (IR) emitters in the filament winding process. This process employs various angles and utilizes a rotatable consolidation axis. The winding process operates at a constant speed, addressing the challenge of bending the fibre-reinforced tapes in the angle reversal areas near the tube ends. Experiments have confirmed that the process can run at speeds reaching approximately 470 mm/min. The design of the impregnation line takes into account the properties of the thermoplastic and the roving, allowing for a speed of up to 1 m/s.}, language = {en} }